using System; 
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq.Expressions; 
using System.Reflection;
using System.Text; 
using System.Linq; 
using System.Data.Linq.Mapping;
using System.Data.Linq.Provider; 

namespace System.Data.Linq.SqlClient {
    /// <summary>
    /// This class defines the rules for inheritance behaviors. The rules: 
    ///
    ///  (1) The same field may not be mapped to different database columns. 
    ///      The DistinguishedMemberName and AreSameMember methods describe what 'same' means between two MemberInfos. 
    ///  (2) Discriminators held in fixed-length fields in the database don't need
    ///      to be manually padded in inheritance mapping [InheritanceMapping(Code='x')]. 
    ///
    /// </summary>
    static class InheritanceRules {
        /// <summary> 
        /// Creates a name that is the same when the member should be considered 'same'
        /// for the purposes of the inheritance feature. 
        /// </summary> 
        internal static object DistinguishedMemberName(MemberInfo mi) {
            PropertyInfo pi = mi as PropertyInfo; 
            FieldInfo fi = mi as FieldInfo;
            if (fi != null) {
                // Human readable variant:
                // return "fi:" + mi.Name + ":" + mi.DeclaringType; 
                return new MetaPosition(mi);
            } 
            else if (pi != null) { 
                MethodInfo meth = null;
 
                if (pi.CanRead) {
                    meth = pi.GetGetMethod();
                }
                if (meth == null && pi.CanWrite) { 
                    meth = pi.GetSetMethod();
                } 
                bool isVirtual = meth != null && meth.IsVirtual; 

                // Human readable variant: 
                // return "pi:" + mi.Name + ":" + (isVirtual ? "virtual" : mi.DeclaringType.ToString());

                if (isVirtual) {
                    return mi.Name; 
                } else {
                    return new MetaPosition(mi); 
                } 
            }
            else { 
                throw Error.ArgumentOutOfRange("mi");
            }
        }
 
        /// <summary>
        /// Compares two MemberInfos for 'same-ness'. 
        /// </summary> 
        internal static bool AreSameMember(MemberInfo mi1, MemberInfo mi2) {
            return DistinguishedMemberName(mi1).Equals(DistinguishedMemberName(mi2)); 
        }

        /// <summary>
        /// The representation of a inheritance code when mapped to a specific provider type. 
        /// </summary>
        internal static object InheritanceCodeForClientCompare(object rawCode, System.Data.Linq.SqlClient.ProviderType providerType) { 
            // If its a fixed-size string type in the store then pad it with spaces so that 
            // comparing the string on the client agrees with the value returnd on the store.
            if (providerType.IsFixedSize && rawCode.GetType()==typeof(string)) { 
                string s = (string) rawCode;
                if (providerType.Size.HasValue && s.Length!=providerType.Size) {
                    s = s.PadRight(providerType.Size.Value).Substring(0,providerType.Size.Value);
                } 
                return s;
            } 
            return rawCode; 
        }
 

    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
